Micro-fluid ejection heads are useful for ejecting a variety of fluids including inks, cooling fluids, pharmaceuticals, lubricants and the like. A widely used micro-fluid ejection head is in an ink jet printer. Ink jet printers continue to be improved as the technology for making the micro-fluid ejection heads continues to advance. New techniques are constantly being developed to provide low cost, highly reliable printers which approach the speed and quality of laser printers. An added benefit of ink jet printers is that color images can be produced at a fraction of the cost of laser printers with as good or better quality than laser printers. All of the foregoing benefits exhibited by ink jet printers have also increased the competitiveness of suppliers to provide comparable printers in a more cost efficient manner than their competitors.
One area of improvement in the printers is in the micro-fluid ejection head itself. This seemingly simple device is a relatively complicated structure containing electrical circuits, ink passageways and a variety of tiny parts assembled with precision to provide a powerful, yet versatile micro-fluid ejection head. The components of the ejection head must cooperate with each other and with a variety of ink formulations to provide the desired print properties. Accordingly, it is important to match the ejection head components to the ink and the duty cycle demanded by the printer. Slight variations in production quality can have a tremendous influence on the product yield and resulting printer performance.
The primary components of an exemplary micro-fluid ejection head are a substrate, a nozzle member (e.g., a nozzle plate) and a flexible circuit attached to the substrate. The substrate can be made of silicon and have various passivation layers, conductive metal layers, resistive layers, insulative layers and protective layers deposited on a device surface thereof. Fluid ejection actuators formed on the device surface may be thermal actuators or piezoelectric actuators, for example. For thermal actuators, individual heater resistors are defined in the resistive layers and each heater resistor corresponds to a nozzle (e.g., a hole) in the nozzle member for heating and ejecting fluid from the ejection head toward a desired substrate or target.
The nozzle members typically contain hundreds of microscopic nozzles for ejecting fluid therefrom. A plurality of nozzle members are usually fabricated in a polymeric film using laser ablation or other micro-machining techniques. Individual nozzle members are excised from the film, aligned, and attached to the substrates on a multi-chip wafer using an adhesive so that the nozzles align with the heater resistors. The process of forming, aligning, and attaching the nozzle members to the substrates is a relatively time consuming process and requires specialized equipment.
Fluid chambers and ink feed channels for directing fluid to each of the ejection actuator devices on the semiconductor chip are typically either formed in the nozzle member material or in a separate thick film layer. In a center feed design for a top-shooter type micro-fluid ejection head, fluid is supplied to the fluid channels and fluid chambers from a slot or ink via which is formed by chemically etching, dry etching, or grit blasting through the thickness of the substrate. The substrate, nozzle member and flexible circuit assembly is typically bonded to a thermoplastic body using a heat curable and/or radiation curable adhesive to provide a micro-fluid ejection head structure.
In order to decrease the cost and increase the production rate of micro-fluid ejection heads, newer manufacturing techniques using less expensive equipment is desirable. These techniques, however, must be able to produce ejection heads suitable for the increased quality and speed demanded by consumers. As the ejection heads become more complex to meet the increased quality and speed demands of consumers, it becomes more difficult to precisely manufacture parts that meet such demand. Accordingly, there continues to be a need for manufacturing processes and techniques which provide improved micro-fluid ejection head components.
The present disclosure includes a method of making a micro-fluid ejection head structure, and micro-fluid ejection head components and structures made by the method. In one embodiment, the method includes providing a substrate having a plurality of fluid ejection actuators on a device surface thereof. The device surface of the substrate also has a thick film layer comprising at least one of fluid flow channels and fluid ejection chambers therein. A removable anti-reflective material is applied to at least one or more exposed portions of the device surface of the substrate. A nozzle layer is applied adjacent to the thick film layer. The nozzle layer is imaged (and in some embodiments developed) to provide a plurality of nozzles in the nozzle layer, and the anti-reflective material is removed from the exposed portions of the device surface of the substrate.
In another embodiment there is provided a method for providing an improved micro-fluid ejection head nozzle member having improved nozzle characteristics. According to the method, a nozzle layer is imaged in the presence of a removable anti-reflective material covering at least exposed portions of a device surface of a substrate to which the nozzle layer is attached. In some embodiments, the imaged nozzle layer is developed to provide a plurality of nozzles therein. The removable anti-reflective layer is removed from the substrate to which the nozzle member is attached.
An advantage of the embodiments described herein can include that they may provide an improved micro-fluid ejection head structures and, in particular, improved nozzle members for micro-fluid ejection heads. Another advantage can include that the methods may enable the formation of nozzles that have a precise size and shape in a nozzle member after the nozzle member has been attached to a micro-fluid ejection head structure. Other advantages of the embodiments described herein may include an ability to readily remove a material that enables such precise nozzles formation in the nozzle member.